This figure shows data from the ADCP (Acoustic Doppler
Current Profiler, RD Instruments) located in the 8m array. Currents and wind data are
separated into cross- and longshore components. The current profile data
are 10-minute averages. It is interesting that the longshore current changes
direction from flowing south to flowing north before the wind changed direction.
This is due to the large waves from H. Isabel approaching from the southerly quadrant,
driving the current to the north.
Click to enlarge

This is a plot of 10-minute vertically
integrated (currents averaged from top to bottom) cross- and longshore
currents, winds, wave height and direction. The top layer (approximately upper 1 m)
is typically not included in the average since data quality is often poor near the
surface. Thus, the cross-shore current may be biased on the negative side (off-shore flow)
since it is missing some of the top layer onshore flow (positive). In addition, with
such a strong longshore current (~200 cm/s) a small rotation in the gage, or what directions
we consider cross- and longshore (we assume cross-shore is aligned with the FRF pier), can
cause a cross-shore bias. Just a 3 or 4 degree rotation could cause significant bias,
approximately 14 cm/s with a 200 cm/s current.
(200 cm/s = 3.9 knots = 4.5 mph)
Data connection was lost just after the peak of storm, around 1550 EST. In the future, data
from a second ADCP located off Kitty Hawk will be included in these plots.
Click to enlarge